Pipe relining method and apparatus

ABSTRACT

A sewer pipe is relined by reaming the old pipe to remove protrusions and obstructions and provide a relatively smooth interior surface; a liner of plastic material is inserted by pulling it along the pipe while vibrating the entire liner from the leading end. Openings are formed in the wall of the liner to provide for lateral connections and these openings are plugged while grout is injected between the inner surface of the existing pipe and the liner, the plugs being removed after the grout has set.

United States Patent [72] Inventor Raymond M. Brenner 102 LynedockCrescent, Don Mills, Ontario, Canada [21 Appl. No. 773,084 [22) FiledNov. 4, 1968 [45] Patented Aug. 31, 1971 [54] PIPE REIJNING METHOD ANDAPPARATUS 8 Claims, 15 Drawing F15.

[52] US. Cl. 138/97, I 138/141, 29/401 [51] Int. Cl. F161 55/18 [50]Field of Search 138/97, 141; 61/45; 137/15; 29/474.4, 433, 401

[56] Referenos Cited UNITED STATES PATENTS 2,522,171 9/1950 Furman138/97 V 2,601,248 6/ 1952 Brenholdt 138/97 V 3,123,101 3/1964 Blount138/97 3,149,646 9/1964 Xenis 138/97 3,294,121 12/1966 Powell.... 138/973,269,421 8/1966 Telford 138/97 FOREIGN PATENTS 1,100,490 4/1955 France138/140 Primary Examiner-Herbert F. Ross Attorney-Thomas Talmon RiederABSTRACT: A sewer pipe is relined by reaming the old pipe to removeprotrusions and obstructions and provide a relatively smooth interiorsurface; a liner of plastic material is inserted by pulling it along thepipe while vibrating the entire liner from the leading end. Openings areformed in the wall of the liner to provide for lateral connections andthese openings are plugged while grout is injected between the innersurface of the existing pipe and the liner, the plugs being removedafter the grout has set.

ATENTEU AUGS] 1911 3,602,263

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FIGS

INVEN'IOR. RAYMOND M. BREMNER ATTORNEYS PATENIED AUG31 I97| 34 92253 sum3 0F 5 INVENTOR. v RAYMOND M. BREMNER F I G. 8

ATTORNEYS ATENIED AUGBI l9?! SHEET 5 [IF 5 Ra a INVENTOR.

RAYMOND M. BREMNER ATTORNEYS PIPE RELINING METHOD AND APPARATUSBACKGROUND OF THE INVENTION This invention relates to a process forrelining pipes, especially sewer pipes in cities, municipalities,townships and villages and waste pipes used in chemical and industrialplants.

In the case of a sewer pipe, incrustation, protrusions and infiltrationthrough joints and cracks inhibit the carrying capacity of the pipe. Atthe present time repairs cannot be carried out without a great deal ofcostly excavation and consequent disruption of the travelled portion ofthe surface because it is generally necessary to replace the whole of adamaged pipe section.

It is an object of the present invention to provide a method of reliningexisting pipes with a minimum amount of excavation and disruption to thetravelled portion of the surface. Basically, this is achieved by reamingthe existing pipe to remove any obstructions and protrusions, andinserting a flexible liner of plastic material. The internal diameter ofthe relined pipe is generally slightly smaller than that of the originalpipe, but the smooth internal surface of the final liner actuallyimproves the flow characteristics of the pipe.

SUMMARY OF THE INVENTION According to the invention a process forrelining a pipe comprises the steps of reaming the pipe to provide asubstantially smooth obstruction free inner surface, providing aflexible tubular liner of plastic material having an external diameterslightly less than the internal diameter of the reamed pipe, andinserting the liner into the pipe. The liner is inserted by pulling italong the pipe while imparting vibratory forces to the liner through itsleading end so as to jiggle it along the pipe.

1n the case of a sewer pipe having one or more lateral connections,openings are formed in the liner in register with the lateralconnections and the openings are plugged while grout is injected betweenthe inner surface of the pipe and the liner, the plugs beingsubsequently removed.

Other features of the invention will become apparent from thedescription which follows, and the drawings referred to therein.

BRIEF DESCRIPTION OF THE DRAWINGS One specific process in accordancewith the invention, and apparatustherefor, will now be described by wayof example with reference to the accompanying drawings, in which:

F 1G. 1 is a fragmentary perspective view of a sewer pipe to be relinedby the process of the invention;

FIG. 2 is a longitudinal sectional view of the sewer pipe during thereaming operation;

FIG. 3 is a perspective view, partly broken away, of a reaming tool forperforming the reaming operation;

FIG. 4 is a section on line 4-4 in FIG. 3;

FIG. 5 is a section on line 5-5 in FIG. 4;

FIG. 6 is an enlarged, exploded perspective view on the detail shown inFIG. 4;

FIG. 7 is a perspective view, partly broken away, of a vibratory nosecone used in the process of the invention;

F lg. 8 is a longitudinal sectional view of the sewer pipe showing thevibratory nose cone in use;

FIG. 9 is a perspective view, partly in section, of an electricallyheated boring tool used in the process of the invention;

FIG. 10 is a schematic block diagram illustrating the control circuitfor the boring tool;

FIG. 11 is a view showing the boring tool in use;

FIG. 12 is a perspective view, partly in section, of an inflata ble plugused in the process of the invention;

FIG. 13 is a view showing the inflatable plug in use;

FIG. 14 is a longitudinal sectional view of the sewer pipe, the figureshowing the pipe after it has been relined and ready for grouting; and

FIG. 15 is a fragmentary sectional view of the sewer pipe after reliningand grouting.

DESCRIPTION OF THE PREFERRED EMBODIMENT The purpose of relining anexisting sewer line is to revitalize the structural strength of the lineand/or to improve the carrying capacity of an existing sewer byproviding a liner free of protrusions, obstructions, incrustations andinfiltration. Prior to undertaking the relining of the sewer it isnecessary to carry out the following preparatory steps:

1. the sewer must be inspected by camera to determine the extent ofdeterioration, deviations from line and grade, and the presence ofobstructions, protrusions and cracks.

2. obstructions and protrusions must be removed, and the sewer must becleaned thoroughly to remove all accumulated debris;

3. the locations of all live drains must be determined;

4. access holes to each private drain must be excavated free from thetravelled portion of the surface; and

5. an access shaft must be excavated at an appropriate distance, whichmay be 300 feet, say, from an existing manhole.

Referring to FIG. 1, a sewer pipe 10 to be relined extendslongitudinally beneath a road having a pavement 11 and sidewalks 12,which provide the travelled portion of the road surface. Lateralconnections 13 to private drains are provided at intervals along thelength of the sewer pipe, each private drain generally having a drainbreather l4. Manholes such as 15 are provided at intervals along thelength of the road to provide access to the sewer.

An access shaft 16 is excavated at a distance (more or less 300 feet)from the manhole l5, and an access shaft (not shown) is also excavatedbeyond the travelled portion of the surface for each private drain 13.

Before the main sewer pipe 10 can be relined it must be reamed to removeobstructions and protrusions. After a long period of use the inside ofthe pipe may be incrusted; the incrustations, together with protrusionsof private drain connections into the pipe form obstructions, shown at18 in FIG. 12, which effectively reduce the cross-sectional area of thepipe and materially impair its flow characteristics. The reamingoperation is performed by means of a reaming tool 19, which is towedthrough the pipe 10 by means of a tow cable 20.

As illustrated in FIGS. 3 to 6, the reaming tool 19 for reaming theinternal surface, of the pipe comprises a cylindrical housing 21 and areaming head 22. Within the housing 21 is mounted a compressed air motor23, having a rotary drive shaft 24 arranged coaxially with the housing21 and projecting from the forward end thereof. Compressed air fordriving the motor 19 is supplied to the motor from an air compressor 25(FIG. 2) through a hose 26 which extends through the rear end of thehousing 21 and is connected to the motor 23. The reaming head 22 is ahollow body consisting of a circular plate 27 welded to an inwardlyextending axial sleeve 28, a generally conical plate 29 having anoutermost cylindrical surface portion 30 welded to the rim of thecircular plate 27 and a swivel coupling 31 closing the forward end ofthe conical plate member 29, the swivel coupling 31 and the sleeve 28being axially aligned. The reaming head is mounted on the rotary shaft24 so as to be driven thereby, by coupling the sleeve 28 to the rotaryshaft 24 and securing them together by bolts 32.

Distributed around the reaming head- 22 are twelve steel plates 33, theoperative surfaces of which comprise particles of crushed carbide bondedon the steel with silver solder. The reaming head 22 is freely rotatablewith respect to the swivel coupling 31, the latter being adapted for theconnection of a tow cable 20 as shown in FIG 2.

A plurality of circumferentially spaced idler assemblies are mountedexternally of the housing 21. Each of said idler assemblies is mountedbetween a pair of longitudinally extending, radially projecting, flangedplates 34, which are bolted to the housing 21 by bolts 35. Each idlerassembly comprises a pair of sprockets 36, which are longitudinallyspaced with respect to the housing, and an endless track 37 carried bythe sprockets. Each sprocket 36 has a pair of stud shafts 38 which arejournaled in holes 39 provided on the inner surfaces of a pair ofelongated guide plates 40, the latter being spaced apart by means of aspacer lock 41 to which they are bolted by bolts 42. Projecting from theouter surfaces of the guide plates 40, near each end thereof, are twopins 43, which engage in radially extending slots 44 in the radialflanges of the flanged plates 34. As best seen in FIGS. 3 and 4, theidler assemblies are biased radially outwardly by means of spring rods45, which pass over bolts 46 projecting from the flanged plates 34 andengage underneath the projecting pins 43. Each endless track 37comprises a flexible, endless chain 47 and a series of friction pads 48carried by the chain. The friction pads 48 are of steel with crushcarbide silver soldered to their outer surfaces. The chain 47 passesround the sprockets 36 in engagement with them, the sprockets beingidler sprockets to permit relative movement between the endless tracksand the housing. The spacer blocks 41 are provided each with a series oflongitudinally spaced recesses 49. The recesses 49 accommodate thrustpads 50 which engage the chain 47 and are resiliently biased bycompression springs 51 to urge the endless tracks 37 radially outwardlyinto frictional engagement with the internal surface of the pipe 10. Byproviding a series of thrust pads 50 for each endless track, differentportions of the track are urged into engagement with the pipeindependently of one another, thus enabling the track to follow morereadily variations in the pipe surface.

In operation of the reaming tool, compressed air is supplied to themotor 23 by way of the hose 26, and the tool is towed through the pipeby means of the tow cable 20. The reaming head 22 is rotated by themotor, so that the operative or cutting surfaces of the plates 33 reamthe internal surface of the pipe and remove protrusions and obstructionstherefrom. The housing 21, which carries the motor 23 is prevented fromrotating by the tracks 37 which engage the internal surface of the pipefrictionally, the tracks 37 providing a large area of contact with thesurface of the pipe by virtue of the resilient biasing means whichenable the tracks to follow variations in the surface contour.

After reaming of the sewer pipe 10, a flexible tubular liner 52 of toughthermoplastic material, such as high density polyethylene, is insertedinto the pipe, the liner having an external diameter which is slightlyless than the internal diameter of the pipe after reaming. Two to fourlengths of tubular liner may be welded together on the site prior toinsertion, depending on how much room is available at the site. As showndiagrammatically in FIG. 8, the tubular liner 52 is (1 through theaccess shaft 16, the leading end of the tubul r liner being secured to avibratory nose cone 53. The nose cone 53 is pulled along the length ofthe pipe 10 by means of a cable 54 which passes round a pulley 55 andextends through the manhole 15. Traction is applied to the cable 54 bymeans of a winch 56.

Referring to FIG. 7, the vibratory nose cone 53 comprises a steelcylinder 57 having four longitudinally extending ribs 58 to which theliner 52 is bolted by means of bolts 59. A blunt nose 60 is welded tothe ribs 58 to close the front end of the cylinder. The cable 54 passesround a pulley 61, which is mounted by swiveling means 62 projectingforwardly from the nose 60 to permit the pulley to swivel freely. Withinthe cylinder 57 is an air motor 63 to which compressed air is suppliedvia an inlet 64, the compressed air being supplied from a compressor(not shown) through a hose 65 connected at one end to the inlet 64. Theleading end of the tubular liner 52 is threaded over the ribs 58 andbolted to them as shown. The air motor 63 is mounted between end plates66, 67, and is coupled to an eccentric rotor 51 which vibrates theassembly in known manner transversely to its axis as the air motor isdriven. By vibrating the leading end of the tubular liner in this way asit is pulled through the pipe, it is possible to overcome resistancewhich could only be overcome otherwise by applying very great tractionforces; these forces might be so high as to damage the liner and theexisting sewer installation.

After the liner is installed, it is necessary to form openings in theliner to register with any lateral connections to private drains, suchas 13. This is achieved by inserting a boring tool through the lateralconnection to bring the tool into engagement with the outer surface ofthe liner. In principal, a rotating cutter of the trepan type could beused, but such tools are inclined to be unsatisfactory when the lateralconnections have awkward bends.

A preferred construction of boring tool for forming the lateral openingsis illustrated in FIGS. 9 and 11, and a control system for the tool isillustrated diagrammatically in FIG. 10. The tool comprises essentiallyan annular cylindrical block of copper, or like heat conductivematerial, 68 which is chamfered at its lower end to provide a narrow rim69. A number of blind bores.70 extend from the upper end of the block 68parallel to the axis of the block, and resistance heating elements 71are located within these bores. Also located within one blind bore inthe block is a temperature sensitive device 72, such as a thermistor.The block 68 is supported by a number of stainless steel support arms73'whose upper ends are connected to a cylindrical boss 74 secured toone end of a flexible rod 75. Electrical leads to the resistance heatingelements 70 and thermistor 72 pass through the rods 73, which aretubular, and are led out by way of an opening 77 as shown in FIG. 9.Alternatively, the rod 75 may be tubular and the leads may be takenthrough the tubular rods 73 and the tubular rod 75.

As shown in FIG. 10, the heating elements 70 are supplied from a DCgenerator 78 in accordance with the operation of a control circuit 79.The control circuit is operated by a temperature indicating device 80connected to the thermistor 72. In use, the boring tool is insertedthrough the lateral connection until the rim 69 comes into contact'withthe thermoplastic tubular liner 52. Current is then supplied to theheating elements 70, to heat the block 68, and at a predeterminedtemperature indicated by the temperature indicator 80 the current to theheating element is cut off by the control device 79. This temperature issuch that the tool can readily fuse its way through the thermoplasticmaterial of the liner, but is well below the flash point of the materialand of any decomposition products that may be formed by the fusion. FIG.11 diagrammatically illustrates the tool in use.

The next step in the relining process is to inject grout between theinner surface of the pipe and the outer surface of the tubular liner;the grout is injected from within the manhole 15 as indicateddiagrammatically in FIG. 14. Before injecting the grout it is necessaryto plug or seal the newly formed openings in the plastic liner, and forthis purpose inflatable plugs 81 (FIGS. 12 and 13) are used.

Referring to FIGS. 12 and 13, an inflatable plug according to theinvention comprises a half-inch diameter steel cable 82 extendingbetween circular end plates 83 and 84. The end plate are formed withshort axially extending flanges, 85 and 86, respectively, to which theends of a cylindrical rubber sleeve 87 are secured by stainless steelbands 88, 89. The leading end of the plug is formed as a nose forguiding purposes, the nose consisting of a number of guide arms 90distributed around a central pipe 91 and welded at their ends to thepipe 70 and the end plate 84, respectively. At the rear end of the plug81 is a coupling member 92 welded to the end plate 83. The couplingmember 92 is formed as a boss having a screw threaded axial recess forconnection to the screw-threaded end of a carrying rod 93. The end plate83 is also formed with an aperture 94 into which a hose adapter 95 isfitted so as to connect an air hose 96.

The normal external diameter of the plug 81 is, of course, less than thediameter of the opening to be plugged. In order to use the plug, one endof the rod 93 is connected to the coupling 92 and the hose 96 leadingfrom a compressed air supply is connected to the adapter 95. The rod 93is lowered through the lateral connection, from the access shaft of theprivate drain, until the plug is positioned in the newly formed openingof the tubular liner. Compressed air is applied through the hose toexpand the rubber sleeve 87 into sealing engagement with the edges ofthe opening. Other openings in the length of the relined pipe areplugged in a similar way. FIG. 13 shows the plug after it has beeninserted into the pipe to close a lateral opening. With the plugs inplace, the grout is injected between the inner surface of the pipe andthe tubular liner 52, and is permitted to set, the plugs subsequentlybeing deflated and removed from the openings.

The arrangement for injecting the grout is illustrated in FIG. 14; thelateral openings and plugs are omitted from this figure for simplicity.As shown in FIG. 14, the ends of the sewer pipe 10 at access shafts l5and 16 are sealed by packing, 97, 98. Two l-inch diameter vent pipes 99,100, are installed through the packing 98 at the bottom end of theaccess shaft 16, the vent pipes projecting into the annular space 101between the liner 52 and the pipe 10. One vent pipe, 100, is equippedwith a valve 102, and the other vent pipe 99 is led to the surface orground level 103. A l-inch diameter vent pipe 104 extends from the topof the access shaft 15 into the annular space 101, and in addition al-inch diameter grout feed pipe 105 is connected between the annularspace 101 and a pump 106 which delivers grout from a grout mixer 107.The grout mix, consisting of one bag of cement to five gallons of water,is then pumped into the annular space 101 through the feed pipe 105.

A visual inspection is made at the lower access shaft 16 to ensure thatthere is a flow of grout from the valve 102; when this flow appears thevalve 102 is closed and pumping is continued until an overflow appearsat both of the vent pipes 99, 104, at ground level..The normal pumpingpressure for the grout is of the order of 2 pounds per square inch, anda pressure of 5 pounds per square inch is considered to be the maximum.Upon completion of the grouting operation, the vent pipes and theinflatable plugs are left in position until the grout is set, thesetting time depending upon temperature and humidity conditions andaveraging about 8 hours.

A section of the relined sewer, after removal of the plugs 81, is shownin FIG. 15. The relined sewer essentially comprises the pipe 10, whichconstitutes a main conduit, the pipe having side openings providinglateral connections to the private drains 13, a flexible tubular liner52 of tough plastic material lining the inner surface of the pipe, theliner having openings such as 108 registering with the side openings 109in the pipe 10, and a filling of grout 110 between the inner surface ofthe pipe and the outer surface of the tubular liner.

When a sewer pipe has been relined in this way, the internal diameter ofthe pipe is slightly less than the original diameter, but because of thenature of the inner surface of the liner the flow characteristics of thepipe are substantially improved.

Although the invention has been described with particular reference tothe relining of sewer pipes, it will be appreciated that it isapplicable to the relining of other fluid pipes whose inner surfaces areliable to deteriorate through constant usage.

What I claim as my invention is:

1. A process for relining a pipe, which comprises:

a. reaming the pipe to provide a substantially smooth obstruction andprotrusion free inner surface,

b. providing a flexible tubular liner of plastic material, the linerhaving an external diameter which is slightly less than the internaldiameter of the pipe,

c. and inserting the liner into the pipe by pulling it along the pipewhile simultaneously vibrating the leading end of the liner in a planetransverse to the axis of the liner.

2. A process according to claim 1, characterized by the further step ofinjecting grout between the inner surface of the pipe and the liner.

3. A process according to claim 1, in which the tubular liner is of highdensity polyethylene.

4. A process for relining a sewer pipe having one or more lateralconnections, which process comprises:

a. reaming the pipe to provide a substantially smooth obstruction andprotrusion free inner surface;

b. providing a flexible tubular liner of plastic material, the

liner having an external diameter which is slightly less than theinternal diameter of the pipe' c. msertrng the liner into the pipe bypulling it along the pipe while simultaneously vibrating the leading endof the liner in a plane transverse to the axis of the liner;

d. providing openings in the liner in register with the lateralconnections;

e. inserting plugs into said openings;

f injecting grout between the inner surface of the pipe and the liner,the grout being retained therebetween by the plugs;

g. permitting the grout to solidify and removing the plugs from saidopenings.

5. A process according to claim 4, wherein the liner is of high densitypolyethylene.

6. A process for relining a sewer pipe having one or more lateralconnections, which process comprises:

a. reaming the pipe to provide a substantially smooth obstruction andprotrusion free inner surface;

b. providing a flexible tubular liner of thermoplastic material, theliner having an external diameter which is slightly less than theinternal diameter of the pipe;

c. inserting the liner into the pipe by pulling it along the pipe whilesimultaneously vibrating the leading end of the liner in a planetransverse to the axis of the liner;

providing openings in the liner in register with the lateral connectionsby fusing through the thermoplastic material of the liner;

e. inserting plugs into said openings;

f. injecting grout between the inner surface of the pipe and the liner,the grout being retained therebetween by the plugs;

g. permitting the grout to solidify and removing the plugs from saidopenings.

7. A process for relining a sewer pipe having one or more lateralconnections, which process comprises:

a. reaming the pipe to provide a substantially smooth obstruction andprotrusion free inner surface;

b. providing a flexible tubular liner of plastic material, the linerhaving an external diameter which is slightly less than the internaldiameter of the pipe;

c. inserting the liner into the pipe by pulling it along the pipe whilesimultaneously vibrating the leading end of the liner in a planetransverse to the axis of the liner;

d. providing openings in the liner in register with the lateralconnections;

e. inserting plugs into said openings, said plugs being inflatablemembers whose dimensions are such that when the members are collapsedthey may be inserted into said openings via the lateral connections, andwhen the members are expanded they fill the openings;

f. inflating said inflatable members to fill said openings;

g. injecting grout between the inner surface of the pipe and the liner,the grout being retained therebetween by the plugs;

h. permitting the grout to solidify;

i. deflating said inflatable members and removing them from saidopenings.

8. A process for relining a pipe having a side opening providing alateral connection, which process comprises:

a. reaming the pipe to provide a substantially smooth obstruction andprotrusion free inner surface;

b. providing a flexible tubular liner of tough thermoplastic material,the liner having an external diameter slightly less than the internaldiameter of the pipe;

c. inserting the liner into the pipe by pulling it through the pipewhile imparting vibratory forces to its leading end;

d. forming an opening in the liner in register with said side opening byapplying a heated element through said opening to fuse through thethermoplastic material, and

e. sealing the edges of said registering openings.

1. A process for relining a pipe, which comprises: a. reaming the pipeto provide a substantially smooth obstruction and protrusion free innersurface, b. providing a flexible tubular liner of plastic material, theliner having an external diameter which is slightly less than theinternal diameter of the pipe, c. and inserting the liner into the pipeby pulling it along the pipe while simultaneously vibrating the leadingend of the liner in a plane transverse to the axis of the liner.
 2. Aprocess according to claim 1, characterized by the further step ofinjecting grout between the inner surface of the pipe and the liner. 3.A process according to claim 1, in which the tubular liner is of highdensity polyethylene.
 4. A process for relining a sewer pipe having oneor more lateral connections, which process comprises: a. reaming thepipe to provide a substantially smooth obstruction and protrusion freeinner surface; b. providing a flexible tubular liner of plasticmaterial, the liner having an external diameter which is slightly lessthan the internal diameter of the pipe; c. inserting the liner into thepipe by pulling it along the pipe while simultaneously vibrating theleading end of the liner in a plane transverse to the axis of the liner;d. providing openings in the liner in register with the lateralconnections; e. inserting plugs into said openings; f. injecting groutbetween the inner surface of the pipe and the liner, the grout beingretained therebetween by the plugs; g. permitting the grout to solidifyand removing the plugs from said openings.
 5. A process according toclaim 4, wherein the liner is of high density polyethylene.
 6. A processfor relining a sewer pipe having one or more lateral connections, whichprocess comprises: a. reaming the pipe to provide a substantially smoothobstruction and protrusion free inner surface; b. providing a flexibletubular liner of thermoplastic material, the liner having an externaldiameter which is slightly less than the internal diameter of the pipe;c. inserting the liner into the pipe by pulling it along the pipe whilesimultaneously vibrating the leading end of the liner in a planetransverse to the axis of the liner; d. providing openings in the linerin register with the lateral connections by fusing through thethermoplastic material of the liner; e. inserting plugs into saidopenings; f. injecting grout between the inner surface of the pipe andthe liner, the grout being retained therebetween by the plugs; g.permitting the grout to solidify and removing the plugs from saidopenings.
 7. A process for relining a sewer pipe having one or morelateral connections, which process comprises: a. reaming the pipe toprovide a substantially smooth obstruction and protrusion free innersurface; b. providing a flexible tubular liner of plastic material, theliner having an external diameter which is slightly less than theinternal diameter of the pipe; c. inserting the liner into the pipe bypulling it along the pipe while simultaneously vibrating the leading endof the liner in a plane transverse to the axis of the liner; d.providing openings in the liner in register with the lateralconnections; e. inserting plugs into said openings, said plugs beinginflatable members whose dimensions are such that when the members arecollapsed they may be inserted into said openings via the lateralconnections, and when the members are expanded they fill the openings;f. inflating said inflatable members to fill said openings; g. injectinggrout between the inner surface of the pipe and the liner, the groutbeing retained therebetween by the plugs; h. permitting the grout tosolidify; i. deflating said inflatable members and removing them fromsaid openings.
 8. A process for relining a pipe having a side openingproviding a lateral connection, which process comprises: a. reaming thepipe to provide a substantially smooth obstruction and protrusion freeinner surface; b. providing a flexible tubular liner of toughthermoplastic material, the liner having an external diameter slightlyless than the internal diameter of the pipe; c. inserting the liner intothe pipe by pulling it through the pipe while imparting vibratory forcesto its leading end; d. forming an opening in the liner in register withsaid side opening by applying a heated element through said opening tofuse through the thermoplastic material, and e. sealing the edges ofsaid registering openings.